Dozer blade, face plate, and edge plate arrangement

ABSTRACT

A dozer blade has (a) a face plate with an exterior surface, (b) an edge plate having a front surface, and (c) a replaceable cutting portion having a front surface and a thickness. The method includes the steps of forming the face plate to include a curved lower portion and attaching the edge plate to the lower portion. Attachment is at a position generally parallel to the projected exterior surface and spaced from the projected exterior surface by a dimension about equal to the thickness of the cutting portion. The method also includes the step of attaching the cutting portion to the edge plate so that the front surface of the cutting portion and the exterior surface of the face plate are generally coextensive. In that way, a &#34;step&#34; in the profile of the blade is avoided and material discharges more readily from the blade.

FIELD OF THE INVENTION

This invention is related generally to earthmoving machinery and, moreparticularly, to such machinery having a dozer blade.

BACKGROUND OF THE INVENTION

A broad category of machines known as earthmoving machines are used inconstruction (and demolition) projects involving moving or removal ofdirt and/or debris. As examples, self-loading scrapers, tractor dozersand the like are used in road construction and such dozers are used todig basements for new buildings. And there are many other uses for suchmachines.

Briefly described, such machines move earth in much the same way that awood plane shaves wood, i.e., by passing a blade across the earthsurface and "rolling up" a layer of earth. Most such machines, which arehard-worked at least because they represent a very substantialinvestment, share a common feature. They have a blade with a main faceplate (the curved plate forming most of the earth-pushing surface) and arelatively narrow, replaceable cutting edge mounted below the plate.

A replaceable cutting edge is desirable for many reasons. The entireblade is a relatively expensive repair component and the use of areplaceable edge greatly reduces the material cost of edge "renewal." Italso reduces the labor cost since irrespective of the size of the blade(which can be several feet long and several feet high), a replacementcutting edge is much easier and quicker to handle than an entirereplacement blade.

A type of known dozer blade with a replaceable cutting edge can, incertain earthmoving operations, be somewhat disadvantageous. Onedisadvantage relates to the fact that in the known blade, the lower edgeof the face plate is "squared off" and presents an abutment-like surfaceon which dirt and other material "catches" as the layer of earth isremoved.

Another disadvantage is that the front surface of the replaceablecutting edge is somewhat forward of the front surface of the main faceplate. As a result, a "step" is formed between the main face plate andthe upper part of the cutting edge.

Because of this step, dirt and other material does not discharge wellfrom the blade. Rather, it "hangs up" on the step as the operator startsto raise the blade and move it away from the pile of dirt being pushed.To put it another way, the blade does not scour properly. And, ofcourse, the more clay-like is the dirt being moved, the more likely itis that such dirt will catch in the step. This can be extremely annoyingto the machine operator who expects that dirt moved to a pile will staywhere placed as the machine moves away from the pile.

Another, less troublesome but nevertheless significant disadvantage isthat to an experienced operator, the presence of the described stepcauses the machine and its blade to behave somewhat differently as dirtis being pushed. In other words, as the blade shaves or "planes" theearth surface, the machine exhibits a "feel" which is different (andless desirable) than that exhibited in the absence of such step.

This is a subjective perception not readily quantified--but there islittle doubt about operator opinion in that regard. A paper titled"SHAPE OF DOZER BLADES TO ATTAIN SMALLEST FILLING RESISTANCE"(translated) discusses dozer blade configuration and performance andhelps understand such perception.

A dozer blade with a replaceable cutting portion which overcomes theaforementioned disadvantages would be an important advance in the art.

OBJECTS OF THE INVENTION

It is an object of this invention to provide an improved dozer bladeovercoming some of the problems and shortcomings of devices of the priorart.

Another object of this invention is to provide an improved dozer bladewherein the main face plate and the replaceable cutting portion aredevoid of a dirt-catching "step."

Another object of this invention is to provide an improved dozer bladewherein the lower edge of the face plate presents a smooth-transitionsurface to dirt being moved.

Still another object of this invention is to provide an improved dozerblade which scours cleanly and from which material readily discharges.

Yet another object of this invention is to provide an improved methodfor making a dozer blade which meets the aforementioned objectives.

How these and other objects are accomplished will be apparent from thefollowing description taken in conjunction with the drawing.

SUMMARY OF THE INVENTION

An aspect of the invention is an improvement in a method for making adozer blade for moving material such as dirt and the like. The blade has(a) a face plate with an exterior surface, (b) an edge plate with afront surface, and (c) a replaceable cutting portion having a frontsurface and a thickness.

The improvement comprising the steps of forming the face plate toinclude an arcuate lower portion and attaching the edge plate to thelower portion at a position generally parallel to the projected exteriorsurface and spaced from the projected exterior surface by a dimensionabout equal to the thickness of the cutting portion.

Such method also includes the step of attaching the cutting portion tothe edge plate so that the front surface of the cutting portion and theexterior surface of the face plate are generally coextensive. When theedge plate front surface and the exterior surface of the face plate areso arranged, a "step" in the blade profile is avoided and materialdischarges more readily from the blade.

The dozer blade includes a backing channel and the preferred methodincludes, in either order with respect to the edge plate attaching step,the step of attaching the arcuate portion and the backing channel to oneanother. The edge plate includes an upper edge and the attaching stepincludes abutting the upper edge against the arcuate lower portion andattaching the edge plate and the arcuate lower portion to one another.

Another aspect of the invention involves an improved dozer blade. In theimprovement, the face plate includes an arcuate lower portion and theedge plate is attached to that curved lower portion. In a highlypreferred arrangement, the edge plate includes an upper edge and theupper edge and the arcuate lower portion are attached to one another.

The cutting portion, the replaceable component of the dozer blade, isattached to the edge plate at a position, i.e., a location and angle, sothat the front surface of the cutting portion and the exterior surfaceof the face plate are generally coextensive. And to help add rigidity tothe blade structure, the blade includes a backing channel and thearcuate lower portion of the face plate and the backing channel areattached to one another.

Further aspects of the invention are set forth in the following detaileddescription and in the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a representative side elevation view of a crawler tractorequipped with a dozer blade.

FIG. 2 is a side elevation of the improved dozer blade with parts brokenaway and other parts in dashed outline.

FIG. 3 is a side elevation view of a portion of the improved dozer bladeshowing a spatial "projection" of the front exterior surface of theblade face plate.

FIG. 4 is a side elevation view of a prior art dozer blade with partsbroken away and other parts in dashed outline.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, the inventive method and dozer blade 10 aredescribed in connection with an exemplary crawler tractor 11, oftenreferred to as a "dozer" or "bulldozer." However, it should beappreciated that as used herein, the term "dozer blade" means a bladeused on an earthmoving machine (e.g., road grader, scraper or dozer),and is not limited to blades used only on machines which are termed"dozers" in a strict sense.

The tractor 11 includes an operator's compartment 13, crawler tracks 15for machine propulsion and a hydraulically-positioned, pivot-mounteddozer blade 10. Using controls in the compartment 13, the operator isable to raise or lower the blade 10 and to "skew" it left or right. Withthis latter capability, dirt or dirt-like material 17 is urged angularlyto one side rather than merely forward as the tractor 15 moves forward.The operator can also tilt the blade 10 so that one end is higher thanthe other.

Aspects of the invention will be better appreciated by first having anunderstanding of the arrangement of one type of known dozer blade 101.Referring to FIG. 4, such blade 101 has a face plate 103 with anexterior surface 105 which is that surface 105 in contact with material17 being moved by the blade 101. The lower portion of the face plateterminates in an abutment-like, "squared-off" lower edge 107. The blade101 also has an edge plate 109 with a front surface 111 and a portion ofsuch surface 111 overlaps the rear surface 113 of the face plate 103when those two pieces are joined together.

The squared-off lower edge 107 and rear-mounted edge plate 109 form arather sharp edge 115 and an abrupt notch 117 in the surface of theblade 101. These features can somewhat impede the progress of material17 sliding up the blade 101. And, of course, any impediment to smooth"filling" of the blade 101 is undesirable.

The blade 101 also has a replaceable cutting portion 119 with a frontsurface 121. Since such portion 119 is thicker than the face plate 103,its upper edge 123 juts out away from such face plate 103. This createsa "step" 125 which, like the edge 115 and notch 117 described above, hasan undesirable effect on the ease with which material 17 moves upwardalong the portion 119 and face plate 103 as the blade 101 is advancedthrough dirt 17, for example.

More noticeable (and more undesirable) is the fact that this step 125impedes the discharge of material 17 from the blade 101 as the blade 101is lifted and moved away from such material 17. Putting it another way,material 17 "hangs up" on the step 125.

Referring now to FIG. 2, the improved dozer blade 10 has a face plate 19with an exterior surface 21 and a curved or arcuate lower portion 23attached to a backing channel 18. Such portion 23 extends rearward andterminates in a generally flat lip 25. As earth or other material 17 isengaged and moves upward along the blade 10, this lower portion 23presents a region of smooth transition 27, quite unlike the sharp edge115 discussed above.

The edge plate 29 (that component which supports the cutting portion 31)has an upper edge 33 which abuts the curved lower portion 23. The edge33 and the portion 23 are rigidly attached to one another, preferably bywelds 35.

The cutting portion 31 has an upper edge 37 and a lower edge 39, thelatter being that part of the cutting portion 31 which bites into andshaves the surface of the earth or earth-like material 17. The cuttingportion 31 (which is the primary wearing part of the blade 10) isreadily replaceable in the field by removing its attachment bolts 41.

FIG. 3 depicts an example of a concept long used by engineeringdraftsmen in that it shows a "projection" of the exterior surface 21 ofthe face plate 19. The line of the projected surface 43 represents thesuch surface 21 and its position as it would be if the surface 21 wereextended further downward and to the right as seen in FIG. 3. Thesignificance of this projected surface 43 will become apparent from thefollowing description.

When making the blade 10, the edge plate 29 is attached to the lowerportion 23 at an angle such that the forward surface 45 of the plate 29is generally parallel to the projected surface 43. And attachment of theplate 29 to the portion 23 is at a position such that the forwardsurface 45 of the plate 29 and the projected surface 43 are spaced fromone another by a dimension about equal to the thickness of the cuttingportion 31. Stated in different terms, the front surface 47 of thecutting portion 31 and the exterior surface 21 of the face plate 19 aregenerally coextensive. Construction of the blade 10 in this wayeliminates the step 125 resulting from the aforementioned jutting upperedge 123 of the cutting portion 119 and material 17 discharges morereadily from the blade 17.

The cutting portion 31 is preferably made of heat treated boron steel.However, such portion 31 may also be made of carbon steel which is notheat treated. A portion 31 made from such carbon steel is likely to beless expensive than one of boron steel--but it will preferably bethicker. And other types of portions 31 may have yet other, differentthicknesses or even different cross-sectional shapes. Notwithstanding,the new method permits attachment of the edge plate 29 to the curvedlower portion 23 at a position and angle such that the front surface 47is in "registry" with the projected surface 43 and thereforeco-extensive with the exterior surface 21 of the faceplate 19.

While the principles of this invention have been described in connectionwith specific embodiments, it should be understood clearly that thesedescriptions are made only by way of example and are not intended tolimit the scope of the invention.

We claim:
 1. In a method for making a dozer blade for moving materialand comprising (a) a face plate with an exterior surface, (b) an edgeplate having a front surface, and (c) a replaceable cutting portionhaving a front surface and a thickness, the improvement comprising thesteps of:forming the face plate to include (a) an arcuate lower portion,(b) a lip extending rearward from the arcuate lower portion andterminating in a lip rear edge, and (c) knee-like transition regionbetween the arcuate lower portion and the lip; attaching the edge plateto the transition region at a position generally parallel to aprojection of the exterior surface, the edge plate being spaced from theprojection by a dimension about equal to the thickness of the cuttingportion; and attaching the cutting portion to the edge plate.
 2. Themethod of claim 1 wherein the dozer blade includes a backing channel andthe method includes, in either order with respect to the edge plateattaching step, the step of attaching the face plate arcuate lowerportion and the backing channel to one another.
 3. The method of claim 1wherein the edge plate includes an upper edge and the attaching stepincludes abutting the upper edge and the transition region against oneanother.
 4. In a method for making a dozer blade for moving material andcomprising (a) a face plate with an exterior surface, (b) an edge platehaving a front surface, and (c) a replaceable cutting portion having afront surface and a thickness, the improvement comprising the stepsof:forming the face plate to include an arcuate lower portion; attachingthe edge plate to the arcuate lower portion of the face plate at aposition generally parallel to a projection of the exterior surface andspaced from the projection by a dimension about equal to the thicknessof the cutting portion; attaching the cutting portion to the edge plateso that the front surface of the cutting portion and the exteriorsurface of the face plate are generally coextensive; the method alsoincluding the step of providing a backing channel and further includes,in either order with respect to the edge plate attaching step, the stepof: attaching the face plate arcuate lower portion and the backingchannel to one another.
 5. In a dozer blade for moving material andcomprising (a) a face plate with an exterior surface, (b) an edge platehaving a front surface, and (c) a replaceable cutting portion having afront surface and a thickness, the improvement wherein:the face plateincludes an arcuate lower portion; the edge plate is attached to thearcuate lower portion of the face plate; the blade includes a backingchannel attached to the face plate arcuate lower portion; and thecutting portion is attached to the edge plate so that the front surfaceof the cutting portion and the exterior surface of the face plate aregenerally coextensive, whereby material discharges more readily from theblade.
 6. In a dozer blade for moving material and comprising (a) a faceplate with an exterior surface, (b) an edge plate having a front surfaceand an upper edge, and (c) a replaceable cutting portion having a frontsurface and a thickness, the improvement wherein:the face plate includes(a) an arcuate lower portion, (b) a lip extending generally horizontallyrearward from the arcuate lower portion, and (c) a knee-like transitionregion between the arcuate lower portion and the lip; the upper edge ofthe edge plate is attached to the transition region; and, the cuttingportion is attached to the edge plate so that the front surface of thecutting portion and the exterior surface of the face plate are generallycoextensive.
 7. The dozer blade of claim 6 wherein the blade includes abacking channel and the face plate arcuate lower portion and the backingchannel are attached to one another.
 8. The dozer blade of claim 6wherein the edge plate includes an upper edge and the upper edge and theface plate arcuate lower portion are attached to one another.